The Catholic community is mourning the loss of a place of worship after the blaze.
The fire brigade was alerted to the fire at the church on the grounds of St Pius X School on Brooklands Rd, about 2.50pm.
Crowds of people lined the street as flames leapt from the church's roof, windows exploded and firefighters battled to bring the blaze under control.
Taranaki assistant area manager John Nicholls said the fire was being treated as suspicious and its cause would be investigated by fire safety officers.
Nicholls said the fire was well alight when firefighters got there.
"Flames were clearly visible from the roof as we arrived," Nicholls said.
Father Craig Butler told the Taranaki Daily News he felt a range of emotions when he heard the news.
"Shock, sadness but a great sense of relief that nobody was hurt," Father Butler said.
"I feel pretty devastated really."
He said the building had celebrated its jubilee in September and generations of families had worshipped there.
"Many have been baptised there and weddings and funerals, so it's a very sad day for our community. Our church was a much-loved place for people to gather. It is a sacred place and it does hold a lot of memories for people."
Father Butler said the parish was grateful to the fire brigade for preventing further damage.
St Pius principal Trish Walsh was on holiday when she heard the tragic news.
"I'm devastated, it's a very sad day," Walsh said.
She said the school's library was in the back of the church and had been destroyed by the blaze.
The school also used the church for its morning prayers and assemblies.
"Our school is incredibly close to the parish," she said. "At the moment we want to do everything we can to support the parish."
Nicholls said firefighters attacked the blaze, which was being fanned by strong winds, with high-pressure hoses from the outside.
"The winds were very strong, blowing smoke and debris across the road, again that is why we maintained an external attack."
At the height of the blaze 26 firefighters and six fire engines were at the scene.
Firefighters remained at the scene until about 9pm.
Neighbour Debbie McGregor said she first knew something was wrong when she saw a line of cars stopped, out of her window.
"Then I saw the smoke coming out of the top of the church," McGregor said.
She said it appeared the fire had caught hold of the building very quickly.
Joe Holden said he couldn't believe it as he watched the church burn. "I went to mass here as a little boy, I grew up going to church here," he said.
"I've attended a lot of weddings, a lot of funerals, a lot of life and said a lot of prayers there."
William Johnston said he had attended mass at the church at Christmas.
"To see it going up in flames is pretty sad," Johnston said.
He said his grandparents had regularly attended the church on Sundays.